题解 | #最差是第几名(二)#

/*
SELECT grade, sum(number) over(order by grade) 
FROM class_grade;

SELECT grade, sum(number) over(order by grade desc)
FROM class_grade
*/
SELECT t1.grade
FROM (SELECT grade, sum(number) over(order by grade) as r
FROM class_grade) as t1
join (SELECT grade, sum(number) over(order by grade desc) as r
FROM class_grade) as t2
on t1.grade = t2.grade
where t1.r >= (SELECT sum(number) FROM class_grade)/2 
and t2.r >= (SELECT sum(number) FROM class_grade)/2;